It is generally well known that there are two distinct types of intermittent urinary catheters typically used by those who are able to do so without the assistance of a healthcare professional. These catheters include lubricated catheters which utilize a gel that is applied to the outer surface of the catheter tube prior to insertion into the urethra and hydrophilic catheters wherein a hydrophilic coating on the catheter tube is activated prior to use by treatment with a liquid such as water or saline solution. In the case of hydrophilic catheters, the liquid which is utilized to treat the hydrophilic coating must be provided by the manufacturer if the catheter is to be delivered to an end user in a ready-to-use condition.
As a result, it is necessary for the hydrophilic coating to either be activated at a point in time just prior to placing the catheter in a package or after placing it in a package. The more common approach is to place the hydrophilic coated catheter in a package together with the liquid. In particular, the liquid for activating the hydrophilic coating on the catheter has typically been placed loosely within the package or it has been in a container placed within the package.
With regard to placing the liquid loosely within the package, this has been found to be an undesirable approach because it presents a spill hazard. The loose liquid is typically provided in a reasonably significant quantity to ensure that there will be sufficient liquid remaining through a commercially viable shelf life to maintain the hydrophilic coating in an activated condition. However, since it is necessary to provide a reasonably significant quantity of the liquid to ensure there will be direct contact of the liquid with the hydrophilic coating following assembly, the liquid can easily spill from the package when the package is opened and may thereby wet and/or stain the end user's clothing. In addition, there is a serious technical problem which relates to the condition in which such a ready-to-use hydrophilic catheter must be sterilized.
Specifically, the sterilization process must take place after the catheter and loose liquid have been sealed within the package. Thus, the catheter is sterilized when the hydrophilic coating is wet, i.e., after it already has been activated by the liquid. However, a wet hydrophilic coating may degrade upon sterilization using conventional techniques, e.g., radiation. In particular, the wet hydrophilic coating may detach from the catheter tube resulting in a bumpy, high coefficient of friction surface.
To avoid such sterilization problems, some manufacturers place a liquid container within the package. According to this arrangement, the end user is provided with instructions to rupture or otherwise open the liquid container to permit the liquid to be released within the package so it can activate the hydrophilic coating. The liquid can be provided in a more limited quantity since the user can be instructed to manipulate the package for a period of time to ensure direct contact of the liquid with the hydrophilic coating immediately prior to use. The technical problem of degradation of a wet hydrophilic coating during sterilization is avoided because the liquid is confined to the liquid container during sterilization which means the hydrophilic coating is in a dry state at time of sterilization. However, there are still drawbacks because the catheter is not in a ready-to-use condition when it reaches the end user since the hydrophilic coating requires activation by rupturing/opening the liquid container and manipulating the package.
There is the continuing presence of a spill hazard even though the liquid may be provided in a more limited quantity. The liquid will be contained loosely within the package interior space holding the catheter after the liquid container has been ruptured to release the liquid so it can easily spill on the end user when the package is opened to remove the catheter. In addition, the presence of the liquid can wet the hands of the end user making it more difficult and messy to handle the catheter.
As noted above, hydrophilic coated catheters typically are provided with a thin hydrophilic coating adhered to the outer surface of the catheter for activation by direct contact with a liquid. When the hydrophilic coating is activated by contact with a hydrating liquid such as water, it provides an extremely low coefficient of friction surface. Whether the hydrating liquid is brought into direct contact with the hydrophilic coating by the manufacturer or the end user, it is generally recognized that it takes around 30 seconds to activate the coating.
In all of these existing products, the catheter therefore depends upon direct contact of the liquid swelling medium (e.g., liquid water) with the entirety of the hydrophilic coated catheter surface for a period of time typically recognized as being 30 seconds. Moreover, all of these existing products achieve direct liquid water contact by providing a package for the catheter that permits liquid water to flow freely within the catheter-containing cavity of the package, and permits unobstructed access of the liquid water to the catheter surface for direct contact therewith. Because of the free flow of loose liquid water within the package and unobstructed access to the catheter surface, it is easy to ensure direct contact of the liquid swelling medium with the entire surface of the catheter that has been treated with the hydrophilic coating.
However, it has remained a technical challenge to provide a urinary catheter which has a hydrophilic coating where the catheter meets all of the important criteria for such a product from the perspective of both the manufacturer and the end user, including the ability to sterilize the catheter without degrading the hydrophilic coating due to wetting prior to sterilization or exposing the end user to a spillage hazard from the liquid water which has been placed in direct contact with the hydrophilic coating.